Clarify between decimal bytes and binary bytes

Gerry Houlder gerry.houlder at
Wed Jul 7 11:43:47 PDT 2010

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I agree with your description of the use of MB versus MiB, but a quick
search of the most common T10 standards show no instance of the use of
either acronym. I'm not sure we should be specifying use of terms that are
not present in T10 standards, but are used in product data sheets.
SAS-2 does use MBps (for Megabytes per second) and correctly defines it as a
decimal entity.
On Wed, Jul 7, 2010 at 11:37 AM, Kevin D Butt <kdbutt at> wrote:
> I believe that the time has come to clear up confusion in the industry
> about the units used in T10 standards.  There should be a clause added in
> each of the standards describing the difference between decimal bytes
> MB = 10^6) and binary bytes (e.g., MiB = 2^20).  There has been this
> definition in IEC for since Dec 1998.
> References:
> I hesitate to bring in a solo proposal to modify SSC-4 or even SPC-4 when
> this issue should apply to all standards.
> Does anybody disagree that T10 should clarify the units being used in our
> standards?
> What is the preferred manner in which we should proceed to make sure this
> clarification is added to each standard?
> Thanks,
> Kevin D. Butt
> SCSI & Fibre Channel Architect, Tape Firmware
> MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
> Tel: 520-799-5280
> Fax: 520-799-2723 (T/L:321)
> Email address: kdbutt at

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